I have an issue that comes and goes on its own. The check engine light will come on, I head to Advance Auto and they pull a code that indicates "catalyst emissions". The OBD that they use does not display a numeric ID# that I have seen.

The car does not hesitate, stall or misfire. I use 93 octane fuel (Shell or Exxon) and drive it daily like Mario Andretti. I mean let it roll, eighty miles an hour to Knoxville, 160 miles round trip with her ears pinned back. She has 132,000 miles on her and still gets 24mpg at these speeds.

Converters do not stink like some that are failing. Then all of a sudden the light will go off for a few days and then its back again. I have had several people suggest quality of fuels can cause this.

Does anyone have a suggestion where to begin to find this fault ?

 

Start with an OBD tool of your own, one that can show live data (they all do codes). Ignore any text supposedly matching any codes and instead look the code up using jag's own data so you get the right info. Do not skip this part!

Post codes by all means, people here know much

I'd get a USB elm327 - amazing value about $20 on ebay. Get the cheapest unless it means waiting longer than you want.

When you've got it and any code, post then someone can explain how to use live data if need be.

 

Thanks, JagV8. I'll look for your suggested USB elm327 on e-bay tonight. I love this forum. I am finding that other Jaguar owners have already experienced some of my issues or know someone who has.